Linux command [File operation]

Introduction

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Text and binary files

text file

A text file is a file in which a character string is written.

• In the text file, only the characters specified by the character code are stored side by side.
• Character code is a character code assigned to a numerical value in order to process or communicate with a computer.
• Example: A is 1000001, B is 1000010, etc.
• Text files are very important on Linux. Most of the setting information related to the OS is managed as a text file.

Binary file

Binary files are image files, audio files, executable files, etc.

• A file that contains numbers other than character codes is called a binary file.
• It is OK to recognize that files other than text are binary files
• The reason why the binary file is garbled by the cat command etc. is that when trying to interpret it as a text file, the numerical value corresponding to the character code was replaced with that character and displayed, so it became a meaningless character string.

1.cat command

Display the contents of the file.

cat [option]<file name>

It is often used without options.

2. less command

A command that scrolls through the contents of a file. Used when viewing the contents of a long file.

less [option]<file name>

It is often used without options.

Scroll operation

Search operation

3. touch command

Command to create an empty file

touch <New file name>

If the file name does not exist, create an empty file, and if it exists, update the time stamp.

4.rm command

Command to delete files and directories

rm [option]<File name to delete>

Note: If you execute the rm command, it will be deleted, not the trash can, so make sure that you can delete it before executing it.

Frequently used options

1.-r Delete the directory as well

rm -r dir

Note: Please note that files and directories in the directory will also be deleted at once. 2.-f Do not display a warning when deleting a file. Not recommended commands

rm -f file

3.-i Check before deleting files

rm -i file

5. mv command

Commands for moving and renaming files

#Concrete example
mkdir dir   //Create dir directory
touch file  //Create an empty file

##File name change
mv file file1

##Move files
mv file1 dir/   //Move file1 into the dir directory

• Behavior changes depending on whether the file or directory is selected.

option

-i Confirm before overwriting

mv -i file file1

6. cp command

Command to copy files and directories

cp [option]<Original>...<Copy to>

##Concrete example
#Copy file
cp file new file
#Copy files to no directory
cp file dir

Note: Be careful as it will overwrite the destination file if it already exists.

option

1.-i Confirm before overwriting

cp -i file new_file

2.-r Copy directory

cp -r dir new_dir

7. find command

Command to search files

find <Search start directory><Search conditions><Search action>

#Concrete example
find . -name README.md -print